The disclosure generally relates to a data processing system and, more specifically, to techniques for calibrating an air-flow sensor for adapter slots in a data processing system.
In many modern data processing systems (e.g., servers), Peripheral Component Interconnect Express (PCIe) adapters are placed at a rear of the systems, which subjects the adapters to upstream preheat from processors, memory, and other components of the systems. In addition, power levels for adapters have generally risen over time. For example, field-programmable gate array (FPGA) modules routinely dissipate 20 to 30 Watts (W). The increased power dissipation and preheat associated with other components of a data processing system have made cooling PCIe adapters increasingly challenging.
While processors and memory usually have built-in temperature sensors that feed into thermal management algorithms of a data processing system, PCIe adapters have been relatively unprotected and rarely have on-board thermal instrumentation that is accessible by the system. In addition, knowledge of the thermal environment (i.e., approaching air speed and air temperature) to which a given adapter is subjected is often times more useful for determining supportability or understanding problems than component temperature alone. Unfortunately, a mechanical layout of an allocated PCIe area (of a data processing system) usually includes multiple narrow slots and/or pluggable cassettes which are not particularly suited for the implementation of standard air speed measurement techniques, e.g., anemometry or pressure taps.
Even when a temperature of approaching air is known, the temperature only represents one piece of information and without additional information (e.g., a speed of the approaching air) diagnosing cooling problems with PCIe adapters is problematic. Information limited to approaching air temperature also does not facilitate the implementation of ‘smart servers’ (with internal knowledge of air-flow) that can adjust fan speeds, as needed, according to the adapters that are implemented.